TEMPERATURE-GRADIENT GEL-ELECTROPHORESIS FOR ANALYSIS OF CLONAL EVOLUTION IN NON-HODGKINS-LYMPHOMA OF THE THYROID

To analyze the transition of an autoimmune disease into a mucosa-assoc iated lymphoid tissue-non-Hodgkin's lymphoma (MALT-NHL), we investigat ed a total of 27 cases of clinically diagnosed autoimmune thyroiditis with lymphoid hyperplasia, Three cases of thyroid hyperplasia sewed as controls. Monoclonal B cells were detected by studying rearrangement patterns of the hypervariable CDR III regions within the immunoglobuli n heavy chain gene locus and the T-cell receptor gamma chain gene (TCR G). We used a seminested polymerase chain reaction (PCR) to demonstrat e immunoglobulin rearrangements and a multiplex PCR for TCRG rearrange ments, The PCR products were analyzed by temperature gradient gel elec trophoresis to expand mixtures of homo- and heteroduplices within hete rogeneous populations of B cells. With this approach we found monoclon ality in 14 of the 27 cases of Hashimoto's disease. In a reinvestigati on we discovered additional histological and immunohistochemical featu res of MALT-NHL in 17 cases. The 14 cases of thyroiditis with clonally expanded B cells clearly demonstrate the transition from autoimmune d isease to non-Hodgkin's lymphoma.